题目内容
(10分)在我国东北寒冷的冬季。狗拉雪橇是人们出行的常见交通工具,如图所示.一质量为30kg的小孩坐在10.6kg的钢制滑板的雪橇上,狗用与水平方向成37°斜向上的拉力拉雪橇,雪橇与冰道问的动摩擦因数为0.02,求狗要用多大的力才能够拉雪橇匀速前进.(sin37=0.6,cos37=0.8,g=10m/s2)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/2014082500404187029309.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/2014082500404187029309.png)
10N
试题分析:对小孩和雪橇整体为研究对象进行受力分析,雪橇匀速运动时有:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250040418851180.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004041901673.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004041932575.png)
联立解得狗拉雪橇匀速前进时用力:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250040419481603.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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